This invention relates to a separation system for removing drilled solids from a drilling fluid being circulated in a well and more particularly to an apparatus and method for such a system having an improved means and method for vibrating the screen apparatus.
Heretofore, it has been common in screening apparatus for the separation or removal of solids from drilling muds or the like to provide means for vibrating or shaking the screens along which the materials being separated are travelling. Such vibration means have, for example, included a pair of oppositely rotating eccentrics which induce vibrations or vibratory motion to the separation means or screens. Also, weight have been provided on the vibratory means which have been eccentrically mounted on parallel shafts rotated in opposite directions. However, such prior art vibrating devices have not produced a generally uniform linear motion parallel to the direction of travel along the separator screens by the materials being separated.
Also, such prior art vibrators for drilling fluids and entrained formation cuttings have imparted a relatively large back and forth vibratory movement to the screen in the direction of travel of the materials along the screen.
A relatively large back and forth vibratory movement of the screen, such as around eight mils 0.008 inch) in each direction for example, results in substantial frictional contact between the screen and solid materials, as well as substantial frictional contact between adjacent solid particles thereby tending to break up or abrade the large particles, some of which may then pass the screen. It is desirable to remove a maximum amount of the solid particles above a predetermined size.